package com.rijndael;

import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;



public class AES2 {

	private static Logger logger = LoggerFactory.getLogger(AES2.class);
     private static final String defaultCharset = "UTF-8";
     private static final String KEY_AES = "AES";
     private static final String KEY = "chips-matrix-aes-by-pengwei";
   /**
    * 加密
    *
    * @param data 需要加密的内容
    * @param key 加密密码
    * @return
    */
   public static String encrypt(String data) {
       return doAES(data, KEY, Cipher.ENCRYPT_MODE);
   }

   /**
    * 解密
    *
    * @param data 待解密内容
    * @param key 解密密钥
    * @return
    */
   public static String decrypt(String data) {
       return doAES(data, KEY, Cipher.DECRYPT_MODE);
   }

   /**
    * 加解密
    *
    * @param data 待处理数据
    * @param password  密钥
    * @param mode 加解密mode
    * @return
    */
   private static String doAES(String data, String key, int mode) {
       try {
           if (StringUtils.isBlank(data) || StringUtils.isBlank(key)) {
               return null;
           }
           //判断是加密还是解密
           boolean encrypt = mode == Cipher.ENCRYPT_MODE;
           byte[] content;
           //true 加密内容 false 解密内容
           if (encrypt) {
               content = data.getBytes(defaultCharset);
           } else {
               content = parseHexStr2Byte(data);
           }
           //1.构造密钥生成器，指定为AES算法,不区分大小写
           KeyGenerator kgen = KeyGenerator.getInstance(KEY_AES);
           //2.根据ecnodeRules规则初始化密钥生成器
           //生成一个128位的随机源,根据传入的字节数组
           kgen.init(128, new SecureRandom(key.getBytes()));
           //3.产生原始对称密钥
           SecretKey secretKey = kgen.generateKey();
           //4.获得原始对称密钥的字节数组
           byte[] enCodeFormat = secretKey.getEncoded();
           //5.根据字节数组生成AES密钥
           SecretKeySpec keySpec = new SecretKeySpec(enCodeFormat, KEY_AES);
           //6.根据指定算法AES自成密码器
           Cipher cipher = Cipher.getInstance(KEY_AES);// 创建密码器
           //7.初始化密码器，第一个参数为加密(Encrypt_mode)或者解密解密(Decrypt_mode)操作，第二个参数为使用的KEY
           cipher.init(mode, keySpec);// 初始化
           byte[] result = cipher.doFinal(content);
           if (encrypt) {
               //将二进制转换成16进制
               return parseByte2HexStr(result);
           } else {
               return new String(result, defaultCharset);
           }
       } catch (Exception e) {
    	   logger.error(e.getMessage(), e);
       }
       return null;
   }
   /**
    * 将二进制转换成16进制
    *
    * @param buf
    * @return
    */
   public static String parseByte2HexStr(byte buf[]) {
       StringBuilder sb = new StringBuilder();
       for (int i = 0; i < buf.length; i++) {
           String hex = Integer.toHexString(buf[i] & 0xFF);
           if (hex.length() == 1) {
               hex = '0' + hex;
           }
           sb.append(hex.toUpperCase());
       }
       return sb.toString();
   }
   /**
    * 将16进制转换为二进制
    *
    * @param hexStr
    * @return
    */
   public static byte[] parseHexStr2Byte(String hexStr) {
       if (hexStr.length() < 1) {
           return null;
       }
       byte[] result = new byte[hexStr.length() / 2];
       for (int i = 0; i < hexStr.length() / 2; i++) {
           int high = Integer.parseInt(hexStr.substring(i * 2, i * 2 + 1), 16);
           int low = Integer.parseInt(hexStr.substring(i * 2 + 1, i * 2 + 2), 16);
           result[i] = (byte) (high * 16 + low);
       }
       return result;
   }
  
}
